DESCRIPTION: The proposed studies will investigate whether fatty acid type and vitamin E concentrations modulate: (1) the amounts of lipid oxidation products isolated from atherosclerotic plaques, and (2) the mechanisms that lead to the formation of lipid oxidation products. NZW rabbits will be maintained on diets enriched in saturated, monounsaturated or n-6 polyunsaturated fat. The diets will contain either high or low concentrations of vitamin E. GC-MS will be used to characterize lipid oxidation products and to infer the mechanisms leading to oxidation assuming that mono-peroxidation products of oleic acid, 3-nitrotyrosine and 3-chlorotyrosine reflect initiation of oxidation by peroxynitrite, free transition metals or Myeloperoxidase, respectively.